There are many circumstances in which it is necessary to provide a positive interlocking relationship between circular elements, or circle segment shaped elements. For example for adjustments for bicycle seats, halo supporting structures for orthopedic procedures, and the like (such as shown in U.S. Pat. Nos. 4,620,530 and 4,913,135, the disclosures of which are hereby incorporated by reference herein). Typically, because of the constraints in manufacture of these components, the surfaces thereof which are designed to mate do not mate over a significant area. As a matter of fact, often the area of mating can be less than 25%. This requires the use of higher quality materials than would otherwise be necessary in order properly hold the surfaces in the particular relative positions to which they have been moved, or poor locking performance results.
According to the present invention, a particular geometrical configuration of the inter-engaging surfaces of interlocking elements is provided which maximizes the engagement area between two cooperating surfaces. Utilizing the geometric configuration according to the invention, it is possible to obtain almost 100% engagement between two cooperating surfaces. This allows the interlocking elements to be constructed of less expensive materials, to be smaller, and/or to provide a better interlocking engagement.
The geometrical configuration according to the present invention that results in the advantages set forth above, and overcomes a longstanding problem in the art with respect to interlocking elements, comprises a plurality of semi-conically shaped surfaces emanating from a common center and disposed in an alternating inverted configuration, and having first and second edges extending in a longitudinal direction. An alternating inverted configuration can be obtained by bisecting a conically shaped element longitudinally, and then translocating the bisected portion so that only one edge of each of the bisected portions is aligned (in a plane perpendicular to the bisecting plane).
The geometrical configuration according to the invention also comprises means for effecting substantially 100% engagement between cooperating conically shaped alternately inverted surfaces. Such means typically comprises a flat surface of substantially constant dimension in a plane substantially perpendicular to the longitudinal direction, and connecting the first and second edges of adjacent alternately inverted semi-conically shaped surfaces. These flat surfaces typically have a dimension perpendicular to the longitudinal direction of about 10-40% of the maximum cross-sectional dimension of the semi-circular conically shaped elements.
The geometric surfaces according to the present invention may be provided in a number of different configurations. For example they may be provided as a circle, a segment of a circle, or a semi-circle, in plan. Alternatively, the conically shaped surfaces may be truncated so as to form a disc, or part of a disc, in plan. The conically shaped surfaces can be hollow, or at least half of the conically shaped surfaces are hollow.
The geometric surfaces according to the invention can be utilized in forming a wide variety of elements for a number of functions. For example if elements according to the invention are formed by cold flow metal stampings techniques, they may be used for bicycle seats or the like. Alternatively elements can be molded of plastic, or vacuum formed from plastic, to provide adjustment components associated with halo supporting structures and like orthopedic devices. In fact, the elements according to the invention can be used in essentially any environment where it is necessary to provide a detachable and adjustable yet positive locking engagement between a pair of elements so that they do not rotate with respect to each other, and in a simple yet effective manner.